I just bought a 70 fastback...my first "vintage" mustang. My dad has a 73 and I was kindad familiar with it. On my '70, I was surprised to be able to see the gastak when I opened the trunk lid. It made em thinkthere was a peice missing but I sure can't find one anywhere...is that the way its suppsoed to be? Dads car has a sheetmetal floor that fits over the tank...